The invention relates to a sun visor for motor vehicles and more particularly to such a sun visor having a mirror and a slider made of a plastic material which serves to cover the mirror and which is guided in the region of its two edge zones extending in the direction of displacement in one guide rail each of a holder made of a plastic material.
In the known sun visors of this kind, use of plastic as material for the slider and the holder contributes towards achieving favorable manufacturing costs and low weight. However, on account of the very large temperature variations to which a sun visor is subjected, the thermal expansions and shrinkages of the slider and the holder forming the guide rails affect the known sun visors to such an extent that the force required to move the slider varies considerably although narrow tolerances are maintained. Even if the dimensions are determined or chosen so that the prescribed force for actuating the slider is reached in the middle of the temperature range, in the two end zones the slider may move of its own accord as a result of jolts or the required actuating force may be much too high.